A casualty is the damage, destruction, or loss of property resulting from an identifiable event that is sudden, unexpected, or unusual. 1  A sudden event is one that is swift, not gradual or progressive. 2  An unexpected event is one that is ordinarily unanticipated and unintended.
exists and is an alternate of . The noble gas notation is a notation formed as a result of the electron configuration notation being used in conjunction with noble gases. The noble gas preceding the element in question is written then the electron configuration is continued from that point onwards. The notation is shorter to write and makes it easier to identify elements.
The six noble gases are found in group 18 of the periodic table. They are Helium, Neon, Argon, Krypton, Xenon, and Radon in order of increasing atomic weight. These elements were considered to be inert gases, as they have a closed-shell configuration, until the 1960's, because their oxidation number of 0 prevents the noble gases from forming compounds readily. This was found to be incorrect in 1962 when Neil Bartlett succeeded in making the first complex xenon compound.